SICK: Eco-terrorists Jeremy Kerr has been jailed for almost nine years

Warped Jeremy Hamish Kerr sent a toxic pesticide in November 2014 to the National Farmers Federation and dairy manufacturer Fonterra.

He pleaded guilty to two counts of blackmail after sending the threatening letters and the case has set back the New Zealand government $37million, NZ Herald reported.

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FORMULA: Kerr threatened to poison the formula

The 60-year-old owned pesticide group Feratox and raked in royalties exceeding almost £50,000.

A court in Auckland heard that Kerr’s sole motivation was financial gain.

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POISON: The case has set the New Zealand government back more than £10million

DNA evidence tied Kerr to the gruesome letter but his lawyers argued that he never intended to carry out the disgusting act.

Justice Geoffrey Venning, who sentenced Kerr, said: “The impact on Fonterra, Federated Farmers and the potential impact on New Zealand's trade relationships with China and other countries was extremely serious.”

New Zealand Prime Minister John Key labelled the threat to New Zealand as “a form of eco-terrorism.”

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PESTICIDE: Kerr owned parted of the pesticide company

Federation Farmers spokesman condemned the incident as a “direct attack on the very fabric of our society”.

Fonterra MD Maury Leyland added that it is “hard to imagine a worse threat to children and families”.

China is the biggest buyer of New Zealand dairy products.

The head of a New Zealand exporters' group said it had seen a fall in Chinese demand after the threat to baby formula.